Alkyl diesters of 3 5-dialkyl-4-hydroxyphenylalkanoic acid

ABSTRACT

PHENOLIC ESTERS HAVING ANTIOXIDANT PROPERTIES ARE DISCLOSED. THE ESTERS ARE DIOL DIALKANOATES. TYPICAL EXAMPLES ARE DECAMETHYLENE DIOL DI-(BIS-(3,5-DITERT-BUTYL-4-BYDROXYPHENYL) ACETATE), AND BEXAMETHYLENE DIOL DI(BIS(3,5-DI-TERT-BUTYL-4HYDROXYPHENYL) ACETATE).

Patented Feb. 1, 1972 t h 3,639,447 may be used to prepare diol dialkanoa es avmg ltferent phenolic groups at the two ends of the dialkanoate mole- ALKYL XEHS cules by carrying out the ester interchange between the George wright Taylor and Derek Harold wood Han, diol and a mixture of lower alkyl esters of different phengate, England, assigum-s Imperial Chemical I d olic acids. In this case a mixture of products would be tries Limited, London, England formed including diesters having different phenolic groups No Drawing. Original application Mar. 28, 1966, Ser. No. at the ends of the molecule. Such mixtures may be used 110W Patent 3,422,059, dated Jallto stabilize polyolefines without separation of the indi- 1969. Divided and this application Mar. 7, 1968, Ser. vidual diesters therein No. 736 865 I 1 Claims p y application Great Britain May 3 1965 0 Preferred diols from wh1ch esters accordlng to the inven 8 516/65 tion are derived are those which contain at least 3 carbon Int CLCMc 69/76 atoms or at least two ethylenoxy groups. us CL 2 0 473 R 4 mi Phenolic diesters wherein a single phenolic group is present in the carboxylic acid from which they are derived are known but these in general exhibit a lesser sta- ABSTRACT OF THE DISCLOSURE bilising eifect, particularly on repeated laundering, than the esters of the present invention. It is preferred that at Phenolic esters having antioxidant properties are disclosed. The esters are diol dialkanoates. Typical examples least g i g grofilp 5 one are decamethylene diol di-[bis-(3,5-di-tert-butyl-4-hy- {110m e groups) 8 011 e presen droxyphenyl) acetate] and hexamethylene diol di-[bism the phenphc fuclel the P 9 hyqroxyl 5 di tert butyl 4 hyd}oxyphenyl) acetate] group, for 1n this way, particularly if this substituent group is a bulky one, the antioxidant effectiveness of the phenolic portion of the diester is enhanced due to steric hinderance of the phenolic hydroxyl group. Compounds i g zgg $2 5 55; g ig ggzigfg ifiggfj according to the invention wherein the phenolic groups s b each have two bulky substituents, as for example tertiary This invention relates to stabilised polyolefines, in parg g z ii ajg i ggs gi i z g m g izgfi fi ticular to polyolefine compositions which, in the form of p y y W g substances. 2 2:3 Ides retam than stablhty after many laundry 30 -Diesters according to the invention protect polyolefines to which they are incorporated against oxidative de- It 15 well known that polyolefines, 111 particular those m containing tertiary carbon atoms, are subject to degradagradatlon and m general to 5 by Welght of the Poly olefine is an effective amount. As polyolefines are also li z i t gn g g glggf a 12: zzi fiz fij azg xg gg subject to other degradative effects it is often desirable to stabilise the polyolefine material against these degradative mc?rporate or i "l ip i stablhsng substances influences with varying degrees of success. Unfortunately as or examp e an H travl'o at 1g t absor at or thermal some of the most effective stabilising agents are unsatisgi zig according to the invention are incorporated 1? i ig l zgg i g sgi g ggg sfi i ig into polyolefines by any method, as for example mixing 2111; 25: 10 s olvent and washing treatments as in dry clean- 4 of the powdered polyolefine with the Solution of the addi' ing and laundering, for the stabilising effect is rapidly five m a volatlle solvent followed by drymg and granlation of the mixture or by mixing the additive directly iol Ztcb; extraction of the stablllser or stabilisers from the into the softened polyolefine in a hot roll or Banbury mixer. We have now found that certain diol dialkanoates are r very effective antioxidants in polyolefine articles and that The present mvenilon may be apphed to l polyplefine Such articles are highly resistant to for example, laun and we have found it to be most useful for lmproving the dering. stability of stereoregular polyolefines, particularly those, According to the invention we provide a stabilised polyi example g lar poly (4-methylpentene-1) or olefine composition wherein there is incorporated either 5 isotactic P yp py from Which u l te e fibres alone or in combination with other polyolefine stabilisers 0f filaments y be Producedan antioxidant which is a diol dialkanoate of the formula The examples which follow illustrate the invention and R n I 1 Eli-11 Il a-n r I 1 H0- bom ,oooxooowrm -o Q-on R2 11 L R4 Ju Where R R R and R are hydrogen, alkyl, or alkoxyl the manner in which it may be performed. In these examgroups, n is 2 or 3, x and y have the value 0, l, 2 or 3 ples all parts are by weight. and A is derived from a diol said diol being an alkane EXAMPLE 1 diol, a thiodialkanol or a poly(ethylene glycol).

Diol dialkanoates according to the invention may be Preparatlon 0f decamethylene (1101 conveniently prepared by ester interchange between the butyl'4'hydroxyphenyl) acetate] relatively high boiling diol and a lower alkyl ester, as for M h l di-(3,5-di-t t b t 1-4-h d o h n l) a etate x p he methyl ester of the approprl te phon h (7.2 parts and decamethylene diol (1.3 parts) are heated acid. The ester interchange reaction may be facilitated together under a flow of nitrogen gas. When the mixture by the use of an appropriate catalyst, as for example, zinc becomes molten tetra-n-butyl titanate solution in nor calcium acetate or a tetraalkyl titanate. This method butanol (1 part in 4 parts of butanol) is added as catalyst for the ester interchange reaction. The mixture is then heated to 1 60170 C. for seven hours, cooled and the solid product, decamethylene diol di[bis-(3,5-di-tert-butyl- 4-hydroxyphenyl) acetate], after recrystallisation from petroleum ether (boiling range 40-60 C.) has a melting point of 172-178 C. The yield of product is 77% of the theoretical amount.

Effectiveness of stabilisation-The diester (0.5 part) prepared as above is incorporated into polypropylene (100 parts) together with a thermal stabiliser, dilaurylp,p -thiodipropionate (0.5 part) and the mixture is melt spun and drawn into filamentary yarn of 720 denier having 144 filaments and 4 turns per inch of twist inserted therein. Hanks of the yarn together with similar yarn containing a commercial antioxidant (the condensation product from 3-methyl-6-tert-butylpheno1 and crotonaldehyde) in place of the foregoing antioxidant are subjected to repeated cycles of a laundering process, which consists in agitating the hanks in boiling soap solution (5 parts of textile soap and 2 parts of sodium carbonate in 1000 parts of water) for 1 hour following by rinsing in fresh water and drying at 140 C. -for one hour in a Wallace ageing oven (H. W. Wallace Co., Croydon, England) until the hank of least partially breaks when subjected to a vigorous tug with the fingers.

Yarn stabilised with antioxidant prepared as described above survives 23 laundering cycles whereas that containing the commercial antioxidant survives only 8-9 cycles.

In an even more severe laundering process, wherein the banks are boiled in the soap solution for 30 minutes and dried in a Wallace oven at 150 C. for 1 hour, stabilised with the foregoing antioxidant according to the invention survives 17 laundering cycles and the control yarn containing the commercial antioxidant survives 6 cycles.

EXAMPLE 2 Preparation of hexamethylene diol di-[bis-(3,5- di-tert-butyl-4-hydroxyphenyl) acetate] Methyl di- 3 ,5 -di-tert-buty1-4-hydroxyphenyl acetate (14.5 parts) and hexamethylene diol (1.8 parts) are heated together under a flow of nitrogen gas at 160-170 C. for about 16 hrs. and a trace of tetra-n-butyl titanate isthen added as a catalyst and the mixture heated at 170 180 C. for a further 23 hours. The mixture is cooled and the solid product hexamethylene diol di- [bis-(3,5-ditert-butyl-4-hydroxy phenyl) acetate] after recrystallisation from petroleum ether (boiling range 100-120) has a melting point of 173-181 C. The yield of product is 80% of the theoretical amount.

When this diester (0.5 part) is incorporated into isotactic polypropylene (100 parts) together with dilauryl- [3,)9-thiodipr0pionate (0.5 part) and spun into yarn as described in Example 1, the resultant yarn survives 15 cycles of laundering according to the more severe laundering process (drying at 150 C.) of Example 1.

4 sation from petroleum ether has a melting point of 120- 124 C. The yield of product is 76% of the theoretical amount.

When this diester (0.5 part) is incorporated into isotactic polypropylene (100 parts) together with dilaurylp,,3-thiodipropionate (0.5 part) and spun into yarn as described in Example 1, the resultant yarn survives 12 cycles (drying temp. 150 C.) of the severe laundering process.

EXAMPLE 4 Preparation of 4,4'-thiodibutanol di- [bis- 3,5-ditert-butyl-4-hydroxyphenyl) acetate] Methyl di-(3,5-di-tert-butyl-4-hydroxyphenol) acetate (7.2 parts) and 4,4'-thiodibutanol (1.3 parts) are heated together under a flow of nitrogen gas. When the mixture becomes molten a trace of tetra-n-butyl titanate solution in n-butanol (1 part in 4 parts of butanol) is added as catalyst for the ester interchange reaction. The mixture is then heated to 180-200 C. for 2 /2 hours, cooled and the solid product 4,4-thiodibutanol di[bis(3,5-di-tert-butyl-4-hydroxyphenyl) acetate] is washed with petroleum ether (boiling range 40-60 C.) to yield a product melting at -69-76 C. The yield of product is 55% of the theoretical amount.

When this diester (0.5 part) is incorporated into isotactic polypropylene (100 parts) together with dilaurylfi, 9'-thiodipropionate (0.5 part) and spun into yarn as described in Example 1, the resultant yarn survives 12 cycles (drying temp. 150 C.) of the severe laundering process.

As one skilled in the art may judge from the foregoing examples diesters according to the invention are effective antioxidants for polyolefines and incorporated therein are very resistant to severe laundering and drying treatments. Simpler esters wherein only a single phenolic group is present at the ends of the diester molecule, as for example the following compounds:

no-Qooo-Qcoo -on and 2 x no-Q-ooo-wmnooo-Qon x 2:

wherein X is a tert-butyl group, survive only 3-6 cycles of the severe (drying at 150 C.) laundering process.

What we claim is: 1. A phenolic ester having antioxidant properties, said ester being a diol dialkanoate of the formula:

R1 R: 1 r l no-bonz),c OOAO o o cum-o {9-011 IR.2 Jn R4 EXAMPLE 3 Preparation of decamethylene diol di-[4,4-bis-(2- L methyl-4-hydroxy-S-tert-butylphenyl) butanoate] where R R R and R are selected from the group consisting of hydrogen and lower alkyl, n is selected from the group consisting of 2 and 3, x and y have a value selected from the group consisting of 0, 1, 2 and 3 and A is derived from a diol selected from the group consisting of alkane diols having 3-10 carbon atoms and monothiodialkanols.

2. A phenolic ester according to claim 1 wherein the phenolic hydroxyl groups are sterically hindered.

3. A phenolic ester according to claim 2 wherein the phenolic hydroxy groups are sterically hindered by two tertiary butyl groups.

6 4. A phenolic ester according to claim 1 selected from References Cited the group consisting UNITED STATES PATENTS (a) decamethylene diol di-[bis-(3,5-d1-tert-butyl-4-hy- 3,497,549 2/1970 Dexter et a1. 26O 473 dmXYPhenYl) acetate], 3,247,240 4/1966 Meier et al. 260-473 am t y di l d1-[ is-( -di-t rtu y y- 5 3,277,148 /1966 Steinberg 2'60 470 droxyphenyl) acetate], (c) decamethylene diol di-[4,4 bis (2-methy1-4-hy- LORRAINE WEINBERGER Puma Exam droxy-S-tert-butyl phenyl) butanoate], and I. F. TERAPANE, Assistant Examiner (d) 4,4 thiodibutanol di-[bis-(3,5-di-tert-butyl-4-hy- 1 Us. CL XR.

droxyphenyl) acetate]. 

